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 Post subject: Re: Two identical sparks, 2 very different range estimates..
PostPosted: Tue Dec 05, 2017 8:49 pm 
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Joined: Sat Jan 14, 2017 4:11 pm
Posts: 97
CSW wrote:
I got the numbers on the 2015 spark showing the lower range estimate today:
After a 50 mile trip, shows 63% used and used 10.4kwh (53% driving and 10% climate control) = so 16.50kwh useable battery??
Isn't that low?


Keep in mind that there is some imprecision in the calculation as the percentage only increments in full % and the kWh in .1 kWh
So you can have up to .9% error on the driving % and .09 error on the kWh, if they cumulate, it can make the calculation of the capacity vary by almost 1 kWh.
To minimize imprecision error, watch the % number and the kWh number, and try to note them when they both change almost at the same time (do keep an eye on the road :) )

Also make sure you are adding all non zero percentages (driving, conditioning and climate), but if possible make measurement when conditioning and climate are at zero, as each of them carries its own imprecision, so if you have to add more than one percentage, the imprecision goes up.

Accounting for the imprecision of the measures, what you found both on the usable capacity and the usage explains the difference of range you mentioned in your first post.

To recap 2016 over 2015
87 over 67 +29%
4.6 m/kwh over 4.1 m/kwh is +12%
17.8 kwh over 16.5 kwh is + 8%

Range based on above number would be 4.6 x 17.8 = 82 miles over 4.1 x 16.5 = 67.65 miles

You can fine tune your estimated usable capacity with more measures following info given above and in other posts.
But between a bit less capacity and a more aggressive driving, your estimated range difference makes sense.


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 Post subject: Re: Two identical sparks, 2 very different range estimates..
PostPosted: Wed Dec 06, 2017 8:36 am 
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Joined: Wed Oct 30, 2013 7:27 am
Posts: 611
Location: Manteca, California
"Also make sure you are adding all non zero percentages (driving, conditioning and climate), but if possible make measurement when conditioning and climate are at zero, as each of them carries its own imprecision, so if you have to add more than one percentage, the imprecision goes up."

Scrambler, you are correct and I should have made this point more clear. Thanks for the clarification.


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 Post subject: Re: Two identical sparks, 2 very different range estimates..
PostPosted: Wed Dec 06, 2017 8:49 am 
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Joined: Wed Oct 30, 2013 7:27 am
Posts: 611
Location: Manteca, California
CSW wrote:
Did the test today on the higher-range 2016.
Drove about 30 miles on the freeway with almost no re-gen.

Came out to used 67% and 11.9kwh.
So 11.9 / .67 = 17.8 kwh usable battery

So when compared to the 2015 spark, the 2016 is showing about 1.5kwh MORE that the 2015 usable at 16.5kwh.

And this is with the lower 2015 Spark number showing some re-gen as half of the 50 mile commute is thru the city with
many stoplights, so the 2015 maybe be ever less than 16.5?? Because it is adding kw during the commute?


For your 2015, try repeating the same freeway route and speed as you used for the 2016. That will give you a better comparison. 17.8 kWh for your 2016 is what I would expect to see. I am going to run the test on my 2016 today and follow with my 2014.

Below are my results for yesterday and today. Only DRIVE had values greater than zero.

2015 Spark EV battery capacity calculation at the end of 35.5 miles was 15.8 kWh [6.0 kWh used or 38% of the battery]. Speed was set to 60 mph and outside temp was 59 deg. F. ODO read 24008 miles at the end of the test trip. Trip meter info: 35.5 miles @ 5.6 mi / kWh. Est range is 89 miles [5.6 mi / kWh x 15.8 kWh].

2014 Spark EV battery capacity calculation at the end of 33.9 miles was 17.8 kWh [6.4 kWh used or 36% of the battery]. Speed was set to 60 mph and outside temp was 53 deg. F. ODO read 12306 miles at the end of the test trip. Trip meter info: 33.9 miles @ 5.3 mi/kWh. Est range is 94 miles [5.3 mi / kWh x 17.8 kWh].

2016 Spark EV battery capacity calculation at the end of 33.8 miles was 17.4 kWh [5.9 kWh used or 34% of the battery]. Speed was set to 60 mph and outside temp was 59 deg. F. ODO read 7776 miles at the end of the test trip. Trip meter info: 33.8 miles @ 5.8 mi / kWh. Est range is 101 miles [5.8 mi / kWh x 17.4 kWh].


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 Post subject: Re: Two identical sparks, 2 very different range estimates..
PostPosted: Fri Dec 08, 2017 8:14 pm 
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Joined: Tue Feb 17, 2015 8:37 am
Posts: 129
Location: Sacramento,CA
Well, it seems to be issue resolved.

I had the wife drive more efficiently (less of a speed-demon) in her 2016 for 2 days.
Then I drove less-efficiently for 2 days in my 2015, tryin to match her 4.1kwh/mi average, and I did.

Yesterday morning both cars were showing 76 miles of range after a full charge......

I still need to do the battery capacity test on the 2015, and I will asap, but I suspect it will be very close to the 2016.

I just did not even think of the average kwh/mi factor because it was so different for so long, AND I do not try to
drive overly efficient, I just drive normal, and I did not consider my wife was worse than me on efficiency. Haha!

Thanks for all the good info and help!


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 Post subject: Re: Two identical sparks, 2 very different range estimates..
PostPosted: Fri Dec 08, 2017 8:20 pm 
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Joined: Tue Feb 17, 2015 8:37 am
Posts: 129
Location: Sacramento,CA
MrDRMorgan wrote:
CSW wrote:
2014 Spark EV battery capacity calculation at the end of 33.9 miles was 17.8 kWh [6.4 kWh used or 36% of the battery]. Speed was set to 60 mph and outside temp was 53 deg. F. ODO read 12306 miles at the end of the test trip. Trip meter info: 33.9 miles @ 5.3 mi/kWh. Est range is 94 miles [5.3 mi / kWh x 17.8 kWh].

2016 Spark EV battery capacity calculation at the end of 33.8 miles was 17.4 kWh [5.9 kWh used or 34% of the battery]. Speed was set to 60 mph and outside temp was 59 deg. F. ODO read 7776 miles at the end of the test trip. Trip meter info: 33.8 miles @ 5.8 mi / kWh. Est range is 101 miles [5.8 mi / kWh x 17.4 kWh].


I find it interesting that the 2014 has a 21kwh battery and the 2016 has a 19kwh, yet the useable capacity is almost the same. Strange GM would do it that way.


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 Post subject: Re: Two identical sparks, 2 very different range estimates..
PostPosted: Sat Dec 09, 2017 1:46 am 
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Joined: Mon May 25, 2015 12:19 pm
Posts: 498
CSW wrote:
I find it interesting that the 2014 has a 21kwh battery and the 2016 has a 19kwh, yet the useable capacity is almost the same. Strange GM would do it that way.

That's because 2014 is 3 to 4 years older and has correspondingly higher battery degradation. New 2014 would have much higher capacity than new 2016, but you need a time machine to compare them since the batteries degrade just by sitting there.


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 Post subject: Re: Two identical sparks, 2 very different range estimates..
PostPosted: Sat Dec 09, 2017 8:53 am 
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Joined: Wed Oct 30, 2013 7:27 am
Posts: 611
Location: Manteca, California
SparkevBlogspot wrote:
CSW wrote:
I find it interesting that the 2014 has a 21kwh battery and the 2016 has a 19kwh, yet the useable capacity is almost the same. Strange GM would do it that way.

That's because 2014 is 3 to 4 years older and has correspondingly higher battery degradation. New 2014 would have much higher capacity than new 2016, but you need a time machine to compare them since the batteries degrade just by sitting there.


I revisited some charging data I recorded starting in March of 2016 and going through June of 2017 for my 2014 and 2015 Spark EVs. The data covers well over 100 L2 charging sessions per vehicle. The average battery capacity for the 2014 Spark EV is 18.20 kWh and the average battery capacity for the 2015 Spark EV is 17.57 kWh as of the end of June 2017. I also plotted all of the average data by month starting in March 2016. The 2014 Spark EV appears to have lost about 1.5 kWh and the 2015 Spark EV was relative stable.


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 Post subject: Re: Spark only showls 65-67 miles of range all the time...LO
PostPosted: Sun Dec 10, 2017 3:59 pm 
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Joined: Wed Oct 30, 2013 7:27 am
Posts: 611
Location: Manteca, California
MrDRMorgan wrote:
scrambler wrote:
MrDRMorgan wrote:
What I do know is adding charge back into the battery will cause the DRIVE value to decrease while the kWh value remains the same. This results in a calculated battery capacity value higher that the actual value. To verify this, I recorded the DRIVE and kWh values shown on the Energy Information screen in my 2016 Spark EV. I then connected the car to my L2 EVSE and charged for about 2 hours. The DRIVE value decreased from 62% to 50%. The kWh value did not change.


I don't know about additional charging with the EVSE, but this is not my experience with regen.

If the car shows a % used and a kWh used and I get a lot of regen, both the % and the kWh used will go back down. So I don't think Regen affects the accuracy of that reading


On Friday I will be driving over a couple of passes where the downhill side does generate considerable regen as I drive in L. I'll try to remember to note the DRIVE % and kWh Used values at the top and bottom to see how the DRIVE and kWh values change. I'll report my findings on Saturday.

Update: This afternoon, I decided to re-test my 2015 Spark EV using the same route as I did in September. I drove on the freeway with the cruise control set to 60 mph. I also configured the display to show any regeneration. I actually had a little regeneration due to overpasses, under passes, and slowing down for traffic but not a amount to be significant. I drove 35.47 miles at an average of 5.6 mi / kWh [6.33 kWh consumed]. The Energy Information screen for DRIVE read 40% at the end of my drive. The calculated HV battery capacity is 15.83 kWh which is almost 1.3 kWh lower than my September calculation and is consistent with a recent problem with the car.

In late October the yellow "Service Vehicle Soon" light came on. I took the car to the dealer and they said there was a problem with the DC charging unit so a repair part was ordered. So far, the part has not arrived. When I got the car back, the light was out, and has remained out, but my battery capacity took a hit and today's calculation is consistent with the drop in full-charge range I have been seeing. I will have to wait to see if the repair part fixes the problem or the dealer finds the problem is really with the HV battery.


Update: I monitored the DRIVE % and kWh Used as I decended the two passes and both times the DRIVE % and kWh Used both decreased simultaneously. So much for blaming REGEN on the HV battery capacity calculations.


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